AP CSA Unit 4: Data Collections — Course Hub

AP CSA · Unit 4 · 17 Lessons

Unit 4: Data Collections

The largest and most heavily tested unit on the AP exam. Master arrays, ArrayLists, 2D arrays, searching, sorting, and recursion — plus the ethical and practical foundations of working with real data sets. Unit 4 is 30–40% of your AP score.

17 Lessons

30–40% AP Exam Weight

170+ Practice Questions

FRQ 3 & 4 Covers These FRQs

All 17 Lessons

Lesson 4.1

Ethical and Social Issues Around Data Collection

Conceptual

Lesson 4.2

Introduction to Using Data Sets

Conceptual

Lesson 4.3

Array Creation and Access

Algorithms with Arrays

Code Mechanics

Lesson 4.6

Arrays as Parameters and Return Values

Code Mechanics

Lesson 4.7

ArrayList Introduction

Traversing ArrayLists

Code Mechanics

Lesson 4.10

Algorithms with ArrayLists

Code Mechanics

Lesson 4.11

2D Array Creation and Access

Searching and Sorting

Code Mechanics

Lesson 4.14

Reading Data from Files

Code Mechanics

Lesson 4.15

Using Data Sets with Arrays and ArrayLists

Informal Code Analysis

Code Mechanics

What you'll learn in Unit 4

The ethical and social implications of collecting, storing, and processing data at scale
How to create, index, traverse, and apply algorithms to 1D arrays of primitives and objects
How to use ArrayList methods and traverse ArrayLists with for and for-each loops
How to declare, create, and traverse 2D arrays using nested loops
How linear search, binary search, selection sort, and insertion sort work and compare
How to read data from text files using File and Scanner
How to trace recursive methods and identify base and recursive cases

Study Guide Unit 4 Complete Study Guide Full unit summary — ideal for review and exam-week cramming Practice AP CSA Test Builder Filter to Unit 4 topics and build a custom practice exam FRQ Prep FRQs by Topic Past FRQ #3 and #4 problems sorted by array and ArrayList Tutoring 1-on-1 AP CSA Tutoring Targeted help from a teacher with a 54.5% score-5 rate

Ready to test yourself on Unit 4?

Build a custom practice exam filtered to arrays, ArrayLists, and data collections.

Build a Practice Exam →

Also in this course

Unit 1 Using Objects and Methods 15 lessons · ~20% of exam Unit 2 Selection and Iteration 12 lessons · ~30% of exam Unit 3 Class Creation 14 lessons · ~14% of exam Unit 4 Data Collections 17 lessons · ~35% of exam You are here

Get in Touch

Whether you're a student, parent, or teacher — I'd love to hear from you.

Typically responds within 24 hours

✓

Message Sent!

Thanks for reaching out. I'll get back to you within 24 hours.

Name *

Email *

I am a... (optional)

Which course? (optional)

Phone (optional)

How did you find us? (optional)

🏫 Welcome, fellow educator!

I offer curriculum resources, practice materials, and study guides designed for AP CS teachers. Let me know what you're looking for — whether it's classroom materials, a guest speaker, or Teachers Pay Teachers resources.

Message (optional — leave blank if just subscribing)

✉

[email protected]

📚

Courses

AP CSA, CSP, & Cybersecurity

⏱

Response Time

Within 24 hours

Prefer email? Reach me directly at [email protected]